Civil Engineering August 2021 | Vol 29 No 7

18 August 2021 Civil Engineering T o achieve emissions targets, annual emissions will need to fall by about 50% between now and 2030 and reach net zero by 2050. A similar target was recently announced by US President Joe Biden for the United States to achieve a 50% reduction in GHG emissions from 2005 levels by 2030. GHG EMISSIONS IN THE BUILDING AND CONSTRUCTION INDUSTRY According to the United Nations 2019 Global Status Report for Buildings and Construction, building construction and operations accounted for 36% of energy use and 39% of CO 2 related emissions in 2018. The emissions produced in the building sector is made up of two compo- nents. The first is emissions arising from operation of the building, which account for approximately 30% of global emissions. The second component, embodied emis- sions, consists of all the GHG emissions associated with building construction, Dr Nicol Chang Pr Eng Technical Director Keller Middle East Africa nicol.chang@keller.com Sustainability in geotechnical construction The authoritative new report by the Intergovernmental Panel on Climate Change sets the world a clear target: we must reduce emissions of greenhouse gases (GHG) to net zero by the middle of this century to have a reasonable chance of limiting global warming to 1.5°C. Transport 28% Transport 23% Other 4% Other 7% Other industry 32% Other industry 31% Construction industry 6% Construction industry 11% Non-residential (indirect) 8% Non-residential (direct) 3% Residential 22% Non-residential 8% Residential (indirect) 11% Residential (direct) 6% Energy Emissions Figure 1 Global share of building construction final energy and emissions, 2018 (Credit: IEA, 2019) GHG emissions Time Operating Extract raw materials Transport to factory Landfill (or recycle) Manufacture products Transport to site Construct the building Use and maintain the building Demolish the building Haul away waste materials Figure 2 Carbon emissions in the lifecycle of structures